Help understanding tax and tax relief on additional / personal pension payments

Hi folks, I'd really appreciate some help understanding how income tax and tax relief on pension payments works. I'm waiting for a callback from a technical advisor but trying to make sure I'm informed before the call. I think the quick question is: - do all pension contributions get subtracted from your gross income before working out how much income tax you pay or does just the tax relief get subtracted? I have earned gross £112,768.99 in tax year 23-24 which includes the subtraction of regular workplace pension contributions. I have then also paid £8399 for added pension from my workplace pension (Civil Service Pension). I understand this is classified as a retirement annuity. I paid this direct from my bank account so this has received no tax relief. I have also paid £6500 to a Self-Invested Personal Pension (SIPP) which has received only basic rate tax relief from the provider. I also declared £1747 untaxed interest as I fell in the £100-150k bracket where I didn't have to complete a self-assessment and couldn't declare this anywhere else. I have written made many many calls to HMRC and have written to HMRC with the evidence required for both additional payments and they've finally contacted me to say they accept the evidence that I've done both these things and have updated my tax calculation but I don't understand the calculation and don't think it's right for lots of reasons: - the calculation subtracts the added workplace pension (£8399) from my gross income before calulating how much tax should be paid but doesn't subtract the £6500 I paid to the SIPP, shouldn't this be subtracted too? - the calculation uses different thresholds for calculating when 20% and 40% tax kicks in - can't understand why this could be possible. The accompanying letter to the calculation confirms that there should be no tapering of my personal allowance but rather than having basic rate 20% tax on the first £37700 (50270 - 12570 personal allowance) the calculation has 20% tax on £45,825? Any ideas why this could be? For the higher rate, I understand the calculation should be: Gross income 112768.99 + 1747 untaxed interest - £6500 pension payment to SIPP - £8399 additional pension payment Civil Service Pension - £500 personal savings allowance - £50270 lower rate threshold = 48846.99 X 40% = £19538. Instead, HMRC have calculated higher rate 40% on £47221 for £18,888.40 higher rate tax? Are HMRC incorrectly netting off the tax relief on these thresholds or incorrectly still applying personal allowance or something? I can't tell from the figures! Any insight welcome! I have a google sheet with HMRC's calculation and my own if I'm allowed to link it here: 

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Hi,
It would depend on the type of pension scheme and the rate of tax being paid. Unfortunately, we are unable to provide specific advice tailored to individual circumstances on this forum. This forum is for general queries only and is intended to help you self-serve. Please refer to guidance at:
 Tax on your private pension contributions.
Alternatively, you may wish to engage the services of a professional advisor/accountant to assist with your enquiry.
Thank you.